Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), so the bar is lower; the description adds genuine value by enumerating what comes back: P/L on a chosen date at a chosen price, P/L at expiration, and the change for one more day, one vol point and a one-dollar move. That effectively substitutes for the missing output schema. It does not cover modeling assumptions or accuracy caveats.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the value proposition followed by per-dimension detail and a concrete example. No filler or repetition of the title.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the return-value burden and does so reasonably well, and the 9-parameter schema (including nested legs and the strategy alternative) is fully self-documenting. The only gap is that it never explains the legs-vs-strategy mutual exclusivity in prose, though the schema states it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, including per-leg fields (qty, days, strike, iv_pct, premium) and the strategy enum, so the baseline is 3. The description only implies the stock_price/days_from_now/iv_change_points scenarios and adds no format or interaction detail beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource: it values an options trade under three scenario dimensions (stock move, time decay, IV change). This is clearly distinguishable in kind from sibling tools like expected_move or probability_of_profit, but the description never names or contrasts those siblings, leaving the differentiation implicit.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

"Use it for questions like what happens to my condor if the stock drops ten percent next week" gives a concrete triggering question, so an agent knows the scenario-analysis use case. It stops short of any exclusion or alternative routing (e.g. when to prefer profit_calculator or probability_of_profit instead).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.